Known in the art is a large variety of devices used to stimulate reflex points of human body. The closest prior art, both in the principle of action and in requirements set to such devices, are vibrators equipped with electromagnetic and electrodynamic systems.
Known in the art is a vibrator (R. C. Bice, Electromechanical Transducer for Vibrotactile Stimulation, the Review of Scientific Instruments, Vol. 32, No. 7, 1961, pp. 856-857) comprising a housing accommodating an excitation coil and a membrane having a load attached thereto.
Since a loaded membrane has a lot of inertia, the housing accommodating the magnetic system becomes a vibrating element. But the Bice vibrator is deficient in that the amplitude of mechanical oscillations produced thereby is frequency-dependent and can reach a maximum of 145 Hz. This is insufficient to stimulate by vibrations human mechanoreceptors. In addition, the vibrator is large, its diameter is 23 mm and its height is 33 mm. The vibrator is relatively heavy, its weight is 47.5 g. It is not easy or even impossible, to secure the vibrator in, for example, the prosthesis sleeve.
Known in the art is a vibrator (Yu. V. Shneider, V. S. Golovin, Vibrator dilia Peredachi Vibratsionnykh Razdrazheny, Sbornik trudov Instituta protezirovania i protezostroenia, Issue 22, Moscow, 1969, pp. 245-249), comprising a housing accommodating an excitation coil. A permanent magnet is installed in the coil and connected to the housing through a set of resilient plates. Interaction of the magnetic fields of the excitation coil and the permanent magnet subject the magnet, acting as a striker, to the torque forcing the permanent magnet to change its initial position. The permanent magnet comes into contact with the skin surface of a biological object through an opening in the housing and in this manner stimulates mechanoreceptors of the biological object.
The amplitude-frequency characteristic of this vibrator is linear within a range of from 0 to 50 Hz. When the frequency exceeds 50 Hz, the oscillation frequency goes down and comes close to zero in the region of 100 Hz. This vibrator is also deficient in that it is made rectangular, 32 by 20 mm in size and weighs 70 grams. This is inconvenient for devices used to stimulate reflex points.
It becomes clear from the above data that prior art vibrators cannot transmit pulsed signals, their vibration amplitude and strike force are insufficient.
Also known in the art is an electromagnetic vibrator (Yu. V. Shneider, V. S. Golovin, Vibrator dlia Peredachi Vibratsionnykh Razdrazheny, Sbornik trudov Instituta protezirovaniya i protezostroyeniya, Issue 22, Moscow, 1969, pp. 245-249) comprising a housing with a cover and an excitation coil arranged on the housing and equipped with a ferromagnetic striking member and a spring. Input signals produce a magnetic field around the coil. This magnetic field is capable to overcome the resistance of the spring to pull in the striker inside the coil. When the input signal discontinues, the striker is pushed by the spring from the coil and strikes the skin. The diameter of the vibrator is 29 mm, the height 17.2 mm, its weight is 50 g. But this vibrator is deficient in that the spring restricts the frequency characteristic of the vibrator to the range of 50 Hz. The vibrator, moreover, is insufficiently reliable when operated for long periods. The size of the vibrator is also a limitation to many types of practical problems.